CH₃ CN@open-C₆₀ : An Effective Inner-Space Modification and Isotope Effect Inside a Nano-Sized Flask.

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Organic Chemistry

Background:

• Fullerene derivatives are extensively studied for their unique electronic and structural properties.
• Encapsulation of small molecules within fullerene cages is a known strategy, but significant modification of the outer cage remains challenging.
• Previous methods for separating functionalized fullerenes often require complex chromatographic techniques.

Purpose of the Study:

• To achieve effective inner-space modification of an open-cage C60 derivative.
• To investigate the structural and electronic consequences of encapsulating acetonitrile (CH3CN) within the C60 cavity.
• To develop a simpler method for separating functionalized fullerenes from unfunctionalized ones.

Main Methods:

• Synthesis of an open-cage C60 derivative.
• Encapsulation of acetonitrile (CH3CN) into the C60 cavity.
• Characterization using NMR spectroscopy, single-crystal X-ray analysis, and Density Functional Theory (DFT) calculations.
• Separation of the functionalized fullerene using column chromatography on silica gel.

Main Results:

• Successful encapsulation of a neutral CH3CN molecule into the open-cage C60.
• The resulting CH3CN@open-C60 exhibits enhanced polarity, enabling easy separation via standard column chromatography.
• Less negative reduction potentials indicate a decreased Lowest Unoccupied Molecular Orbital (LUMO) energy level, confirmed by DFT calculations.
• Both the encapsulated molecule and cage deformation contribute to the observed changes in electronic properties.

Conclusions:

• Inner-space modification of open-cage C60 with CH3CN is an effective strategy for altering fullerene properties.
• The enhanced polarity facilitates simpler purification, overcoming limitations of previous methods.
• The study highlights the interplay between encapsulated guests, cage structure, and electronic properties in fullerene chemistry.
• Investigated the favored binding affinity of deuterated acetonitrile (CD3CN) with the internal C60 surface.